Readers of the blog may recall that I covered Gerardo Aldana’s article on the problems of the GMT correlation constant(s) almost 1.5 years ago. He argues that the correlation issue has not been resolved and that it may be off by at least 60 days. One of his arguments relates to Stela 3 at the site of Poco Winik (or Poco Uinic) which contains a known Classic period inscription that probably mentions an eclipse. Aldana writes that, “the one record from the Classic period, then, with the potential for identifying a unique date astronomically does not conform to any version of the GMT. Rather than call into question the GMT, this has led to speculations about the authenticity of the record itself; more often than not, however, the Poco Winik data is left outside of the discussion.”
In a recent discussion on facebook that has partially spilled over on one of my old posts on Aldana’s article, Barbara MacLeod points out several interesting observations by her and Michael Grofe. The eclipse date in question on the monument is 220.127.116.11.16 5 Kib 14 Ch’en G6 (15 July 790 according to GMT+2). The reason why Aldana is skeptical is that the actual eclipse occurred on 16 July 790 and hence the eclipse would only suit a GMT+3 correlation, and this is one day off from the correlation favored by Lounsbury and three days off from the correlation favored by 2012ers. MacLeod believes it still fits the GMT+2 correlation because the Long Count was synchronized with the tzolkin and both changed at sunset and the haab date began at sunrise. Based on Malmstrom, MacLeod believes that “Maya Day 1425516 (5 Kib) began at sunset on July 15, 790 (J) and 14 Ch’en arrived at sunrise. It was still 5 Kib 14 Ch’en when the eclipse occurred at midday, but the JDN, which changes at noon, had shifted forward from 2009801 to 2009802” (quote from facebook, April 13). See my earlier post on when the day began.
One of the issues with the GMT+2 correlation is that this is not corresponding to the tzolkin being used in the highlands of Guatemala today (see my post on Barbara Tedlock’s work at Momostenango). There is a two day discrepancy between the Classic period tzolkin and the current one and this is one of the reasons why Thompson finally settled for the GMT correlation (the one favored by 2012ers). This is also the 260-day cycle being used in Central Mexico at the time of the Spanish conquest. On facebook MacLeod mentions Lounsbury’s explanation of the two-day discrepancy that I find convincing. He “refers to the strong Postclassic Central Mexican presence in the highlands of Guatemala prior to Spanish contact, and assumes that the political/religious structure of those communities was both (1) internally synchronized (down to the smallest villages) and (2) subject to authoritarian decrees which included reconciliation of the tzolk’in (and presumably the haab) with the 584283 [GMT] correlation constant found in Central Mexico” (quote from MacLeod on facebook, April 13). I speculate that the Aztecs may have wanted to synchronize their New Fire ceremonies throughout their hegemonic empire.
In short, the evidence seems to point to December 23, 2012, being the date of 13 baktun.